<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>LOGO</title>
<style>
canvas { border:1px solid gray; }
</style>
</head>
<body>
<canvas id="canvas" width="512" height="512"></canvas>
<script>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");

ctx.beginPath();
ctx.lineTo(70, 30);
ctx.lineTo(350, 30);
ctx.lineTo(440, 130);
ctx.lineTo(440, 480);
ctx.lineTo(70, 480);
ctx.closePath();
ctx.fillStyle = '#05a8ec';
ctx.fill();    
ctx.lineWidth = 5;
ctx.stroke();

ctx.beginPath();
ctx.lineTo(350, 30);
ctx.lineTo(350, 130);
ctx.lineTo(440, 130);
ctx.stroke();

ctx.fillStyle = "black";
ctx.font = "bold 400px 方正粗圆简体";
var text = "⇅";
var x = (canvas.width - ctx.measureText(text).width)/2;
ctx.fillText(text, x, 400);
</script>
<body>
</html>